Supermodeling for Skeptics

In which we explore the difference between the search for The Absolute Truth, and the search for A Useful Explanation So We Can Get On With Our Lives and Maybe Catch A Movie Later.

My mother and I were chatting on-line the other night. Now, my mother is 62 years old, and a little before the Wired Generation. Hey, I consider myself older than the Wired Generation, but I'm a computer geek. So is my stepfather. My mother just entered the world of instant messaging in the last month, got a cell phone two years ago, and started using email extensively only about 6 or 7 years ago. My father and stepfather and I have been entirely wired for more than 10, 12, and 15 years respectively. We're technology geeks. My mother is not.

What my mother is, however, is a scientist, trained in careful observation and rigorous thought. She has her PhD in Biochemistry, my father has his in Chemistry, my stepfather's is in Geology, and my stepmother (a more recent addition) has hers in Microbiology. I myself am the ignorant one of the family (except my sister , who is only 21 and hasn't finished school yet) with a B.S. in Physics, and a 17 year career teaching computers to sit up on their hind legs. However, with all those hard science folks running around I've soaked up some of their attitude toward how reality works. I'm a skeptic, and to a great degree, so is my mother.

On the evening in question, the above mentioned sister had sent us a digital picture of her boyfriend, dressed in his dress blues as a recent graduate of Marine boot camp. Mom and I are discussing it.

Mom: Did your sister send you the picture of her boyfriend?
JT (me): nod I saw it at work, but didn't save the URL. Do you have it?
Mom: He looks so young.
JT: I was thinking how big his eyes were.
Mom: http://www.dickinson.edu/~hozikm/Josh_Blues.JPG
I was thinking deer-in-the-headlights, myself.

Some intervening conversation, while looking at the picture. Suddenly I'm struck by part of the image I hadn't noticed before at work.

JT: Ummm... do you notice a double image on this picture?
Mom: I see some streaks extending to our left from the brim of his hat, if that's what you mean.
JT: What I see is a little finger extending from his middle jacket button toward his right collar button? And a ring finger extending through his top button and touching the tip of the little finger. And part of right hand extending from our left and touching the left hand fingers I just mentioned.

I'm chilled. Here's a young man, possibly going to war and endangering his life, and there are ghostly hands upon him. Wild. Could they be from a guardian angel, or God? I'm primed to believe by the late hour, and my deeply buried Irish soul has been revealed like the contents of an archeological dig by a couple bottles of Guinness. Unfortunately, my mother can't see them on CRT as well as I can on my laptop screen. More back and forth, as I describe the details, and some stretch of time where we are both silent, contemplating that same mystical vision.

JT: Wait, wait! I've got it! It's a digital picture. My sister didn't scan it, she took a picture of it with her digital camera. The picture was framed... and under glass!
Mom: So those are her hands?
JT:Right! And the streaks are the top of the camera.
Mom: ...Are the hands coming from either side? Could we tell her that it looks like she's strangling him?
JT: ...no, at most it looks like she's rubbing his shoulder...

This serves to prove two things. First, my mother has a wicked sense of humor at times. Second, it's not difficult to get caught up in an explanation for an event, even if it's nonsense, if it serves some compelling purpose. I'm going to call the explanation, right or wrong, the Model, and the phenomenon being explained, the Subject. Generally, in day to day life, you observe some Subject event, and try to come up with a Model which will describe and predict its behavior. The ancient Greeks were great at this, in the sense that they were very imaginative in constructing Models. They were a little weak in the testing phase, though, which gave them notions we find quaint.

Science serves Man by giving us a rigorous framework for constructing and testing Useful Models. For instance, the work of Copernicus, Galileo, and Newton (among many others) gave us a view of the universe as a sensible series of causes and effects. This Model could be called Classical Determinism. The Model implies that reality works the same from minute to minute, and in different physical locations. It provides a way to make predictions of the future behavior of objects. This allows you to Get Things Done like building bridges, predicting eclipses, and sending things near or to other planets.

But, as they say about Camelot in Monty Python, "It's only a Model!" Classical Determinism is the explanation for phenomena, not the phenomena themselves. It's very convincing, since in general it fits in with our day to day experiences -- putting aside that round Earth that moves around the Sun, instead of vice versa, thing. It becomes even more convincing when it lets us predict things we wouldn't expect from common sense.

In the late 19th century, scientists started messing about with things they couldn't see or throw off of tall buildings. The trouble started earlier with Chemistry and the fall of the phlogiston theory, and got a lot worse with the study of electromagnetism. Then radioactive Subjects were investigated and all hell broke loose. The old Models didn't cover energy which wasn't part of things moving, or about to move.

Since the scientists couldn't directly handle the components of the Subject, they started using their imaginations, and complex mathematics, to generate their Models. Then, they would test the Models by looking for Subject to support or disprove them. This process, you'll note, is the reverse of the classical one above.

Scientists also had at their disposal new mathematical tools, such as tensors and other deadly weapons of mental destruction I have repressed since college. This allowed them to create ever more complex Models, ones that would Model the observed Subject in interesting ways. Complex ways. Ways that the Model inventor may not even know.

Let's go back to the Phlogiston Theory. Essentially, the phlogiston theory was a model which explained combustion and respiration. When charcoal burns, it gives off phlogiston, which makes the remaining ash lighter. If the charcoal is in an enclosed space, pretty soon the space fills with phlogiston, smothering the fire. A mouse gives off phlogiston as it breathes. If in an enclosed container, it can "drown" when the container fills up with phlogiston, just as the charcoal did.

This Model serves perfectly well for the Subjects of the mouse and the piece of charcoal. Of course, instead of deciding the charcoal and mouse release phlogiston, you could decide that it makes more sense that they consume something... Agent X. The charcoal combusts, and in the process uses Agent X until there is no more in the closed container. The mouse breathes in Agent X and doesn't release phlogiston. When the Agent X is used up, the mouse can no longer breath it in, and dies. The same results are obtained, whether you suppose manufacture of Phlogiston or consumption of Agent X. You can burn other things, and get predictable results. You can put other animals in enclosed spaces, and achieve predictable results. You can even estimate how long an animal of a given weight will last in an enclosed space of a given size, whether you imagine he's releasing Phlogiston or consuming Agent X, even though the Model is totally opposite.

Which is true? Well, we know that if we try to add other Subjects to the set, the Phlogiston Model rapidly falls apart. Some things burn and get heavier, some burn and get apparently lighter. And my favorite, if you float a candle on a pool of water under an inverted glass jar... the water level will rise, implying that something is being consumed in the air of under the jar. That something, Agent X, is Oxygen.

Up to the point we saw the Model break down, there was no way for us to distinguish between the two opposing explanations. Were they both equally true? Depends what you mean by true. Were they both equally functional? Yes!

Consider the FAX machine. One explanation for its function is that there's an electronic mechanism which translates dark and light areas on your original to signals, and sends them over the phone line, where they are converted into patterns of dark ink on the other end. Another explanation might be that there are little blue Venusians who read your original aloud over the phone to a similar set of Venusian painters on the other end of the line. Which Model is true?

There are two ways to argue. First, you can argue simplicity. Electronic gadgets are known to exist, the FAX has to plug into a wall outlet, and we've never seen a blue Venusian 'round these parts. The pro-Venusian contingent might say "Well, just because there are ducks in ponds doesn't mean there's one in your bathtub (and so there may not be electronic gadgets in the FAX), the Venusians need light to see your original, and of course you haven't seen the blue Venusians, they're all busy FAXing."

Second, of course, you can open the FAX machine, and point out the electronic gadgets and utter lack of blue Venusians. This is pretty conclusive. However, there are plenty of problems which do not admit to such a straightforward solution.

Two varieties of these problems make up the bulk of modern physics: Quantum-level (very very small details, sub-atomic) and Cosmological (things incredibly large and far away). You can't just open up a proton and look inside. You can, however bash protons into each other and see what kind of stuff flies off, or bounce a photon off one and see where it goes. This is kind of like crashing two cars into each other to see what sized tires they have, or blindfolding yourself and rolling a bowling ball down an alley to see which pins are still standing. The problem is, that our tools for examining really small things are about the same size as the thing itself. We're too ham-handed and nearsighted to be able to tell what's inside by just looking. So, we make up a Model, out of whole cloth and higher mathematics, then see if it responds the same way the real Subject seems to. When we have a Model which does respond indistinguishably, we use it to make predictions, and we test those predictions.

It's hard to poke a quasar and see how it jiggles, or put it under a glass jar. All you can do is observe its characteristics and make up plausible (or less plausible) explanations for them. When you finally end up with a Model which accounts for all the characteristics of a quasar, you shake it to see if any predictions can be made of other, yet unobserved behaviors. Then you go looking for things which fit those predictions.

Lest you think that it's just ancient Greeks and 18th century folk who put blue Venusians in their Models, the current physics establishment does the same. We all remember the Electron, Proton, and Neutron from our grade school science classes, but throughout the 20th century, other particles were discovered. They are classed into leptons (light particles such as the electron, neutrino, and photon), mesons (medium weight particles such as the pion and kaon) and baryons (big mothers such as the proton, neutron, and the omega particle). The latter two categories are lumped into "hadrons".

So many hadrons been discovered by the 1960s that scientists started to doubt that these were elementary particles at all. It offends scientists when their models get increasingly complex (the current list includes 14 baryons, and 19 mesons!). When we bash some of these particles together, they break up into other particles in certain repeatable ways. What a mess. So, they decided to simplify things by inventing a building block for hadrons known as the quark.

Instead of thinking a proton is an indivisible, fundamental building block, quark fans think of it as being made up of three quarks...two Ups and a Down. A neutron is made up of two Downs and an Up. Each one of the hadrons in turn made up of two (mesons) or three (baryons) quarks. There are six varieties of quarks, known as Up, Down, Top, Bottom, Strangeness, and Charm. These names should not be considered to have literal meaning, it's just easier to remember than calling them Thingy1, Thingy2, etc. There are also the anti-matter versions of each of these six varieties, for a total of 12 building blocks.

The tricky thing about quarks is... they don't exist. They don't exist in the way we usually think of things existing, independent of our thoughts about them. They are a construct, a bookkeeping convention, which lets us "simplify" our Elementary Particle Zoo from 33 members (and growing) to 12, and give us a way of describing the ways one of the 33 zoo inmates can transform into another in our experiments. Nobody's seen direct evidence of a quark, just things which can be described by assuming the existence of quarks.

There's at least one other system for describing these things. You can see it at www.infiniteparticlephysics.com. Note that I have not reviewed the details of this person's Model, and it could be utterly tinfoil hat wacko. However, it doesn't use a single quark.

So, you've got your utterly fictional Model, grown from whole cloth goodness in the fertile ground of your imagination from an ugly rumor and a blind date you had once. And, we've got your handful of Subjects, which your Model explains just fine. Your buddy, two countries over, has come up with an entirely different Model based on a childhood story and a pair of old socks, but it fits the same handful of Subjects yours does. Which is true? Which is functional? Who cares?

You win if a new Subject is observed which fits your theory and not his. But is this conclusive? What if some third scientist, perhaps one of those nosy blue Venusians, has come up with a third Model which covers all the known Subjects but contradicts yours on a fundamental level? Who's right now? Not the guy with the old socks, at least, but which Model remaining is Truth?

The Subjects are Truth, outside the Model, where they can be tested, while the inside of the Model is Fantasy, because it cannot be tested. So if I tell you that an ugly rumor saying that particles can exists for incredibly short periods of time, as long as the universe isn't looking, is the Truth, I'm confusing my Model with my Subjects. If your buddy tells you there are two additional old socks that you cannot see, he's confusing his explanation with the things he's trying to explain. If the blue Venusian is covered in toner and tells you he works in a FAX machine, you might be on(to) something.

It's easy for people to confuse their Models with their Subjects. It doesn't just happen in Science. It happens in religion, and it happens in politics. It happens when companies start believing their own press releases. Practice rational thought, and remember the difference.

And if you see a blue Venusian, tell him to come back to work. I'm expecting a FAX.

Article © John Trindle. All rights reserved.
Published on 2005-04-10